Facial feedback hypothesis
[3] This is reflected in studies investigating emotional experience in facial paralysis patients when compared to participants without the condition.
[6]: 463 In other words, in the absence of awareness of bodily movement, there is only intellectual thought, with consequently the mind being devoid of emotional warmth.
During this period, the posits culminating in the facial feedback hypothesis lacked evidence, apart from limited research in animal behavior and studies of people with severely impaired emotional functioning.
One of the first to do so, Silvan Tomkins wrote in 1962 that "the face expresses affect, both to others and the self, via feedback, which is more rapid and more complex than any stimulation of which the slower moving visceral organs are capable".
For example, arguably one of the most—if not the most—influential studies on the facial feedback hypothesis was conducted by Fritz Strack, Leonard L. Martin, and Sabine Stepper in 1988.
Strack, Martin, and Stepper pioneered a technique in which researchers were able to measure the effect of the actions of smiling and frowning on affect through inducing such expressions in an undetectable manner to the participant, offering a supposed level of control not yet before utilized in similar studies.
Furthermore, Lanzetta et al. (1976) conducted an influential study[16] in support of the facial feedback hypothesis finding that participants who inhibited the display of pain-related expression had lower skin conductance response (a measure commonly used to measure the activation of the sympathetic nervous system, or stress response) and subjective ratings of pain, compared with participants who openly expressed intense pain.
However, the higher funniness ratings of the cartoons obtained by those participants "tricked" into smiling may have been caused by their recognizing the muscular contraction and its corresponding emotion: the "self-perception mechanism", which Laird (1974) thought was at the root of the facial feedback phenomenon.
Told they were taking part in a study to determine the difficulty for people without the use of their hands or arms to accomplish certain tasks, participants held a pen in their mouth in one of two ways.
The cover story and the procedure were found to be very successful at initiating the required contraction of the muscles without arising suspicion, 'cognitive interpretation of the facial action,[18] and avoiding significant demand and order effects.
[20] A subsequent analysis by Noah et al.[21] identified a discrepancy in method to the original 1988 experiment as a possible reason for the lack of systematic effect in the replication series.
Several studies have examined the correlation of botox injections and emotion[24][25] and these suggest that the toxin could be used as a treatment for depression.
It has been suggested that the treatment of nasal muscles would reduce the ability of the person to form a disgust response which could offer a reduction of symptoms associated with obsessive compulsive disorder.
[26] In a functional neuroimaging study, Andreas Hennenlotter and colleagues[27] asked participants to perform a facial expression imitation task in an fMRI scanner before and two weeks after receiving botox injections in the corrugator supercilii muscle used in frowning.
A study by Mariëlle Stel, Claudia van den Heuvel, and Raymond C. Smeets[29] has shown that the facial feedback hypothesis does not hold for people with autism spectrum disorders (ASD); that is, "individuals with ASD do not experience feedback from activated facial expressions as controls do".
